Endress+Hauser Liquisys M CCM223 - Page 61

Liquisys M CCM223/253 Commissioning
Endress+Hauser 61
Limit contactors for chlorine/chlorine dioxide/total chlorine measured value and
temperature or pH or ORP measured value
The transmitter has different ways of assigning a relay contact. Switch-on and switch-off
points and pickup and dropout delays can be assigned to the limit contactor. In addition,
you can configure an alarm threshold to output an error message and to start a cleaning
function in conjunction with this.
These functions can be used both for the primary value and for temperature measurement.
Please refer to the switch states in →  36 for a clear illustration of the relay contact
states.
• When the measured values increase (maximum function), the relay contact is closed as
of t2 after the switch-on point (t1) has been exceeded and the pickup delay has elapsed
(t2-t1).
The alarm contact switches if the alarm threshold (t3) is reached and the alarm delay
(t4-t3) has also elapsed (errors E067 to E070).
• When the measured values decrease, the alarm contact is reset when the value falls
below the alarm threshold (t5) again, as is the relay contact (t7) after the dropout delay
(t7-t6).
• If the pickup and dropout delays are set to 0 s, the switch-on and switch-off points are
also switch points of the contacts.
The same settings can also be made for a minimum function in the same way as for the
maximum function.
t
1
t
1
t
2
t
2
t
3
t
3
t
4
t
4
t
5
t
5
t
6
t
6
t
7
t
7
t
t
B
1
2
3
3
2
1
4
5
6
7
4
5
6
7
A
A0025215
 36 Illustration of the alarm and limit value functions
A Switch-on point > switch-off point: Max. function
B Switch-on point < switch-off point: Min. function
1 Alarm threshold
2 Switch-on point
3 Switch-off value
4 Contact ON
5 Alarm ON
6 Alarm OFF
7 Contact OFF